LIFETIME MEASUREMENTS OF CFX RADICALS AND H-ATOMS IN AFTERGLOW OF CF4H-2 PLASMAS/

Decay time constants of CFx radical and H atom densities were measured in the afterglow of high-density CF4 plasmas following the addition o f H-2. The lifetimes of CFx and H for high H-2 partial percentages (> 25%) were several tens of times longer than those for low H-2 partial percentages (<15%). The long lifetimes of both CFx and H observed for high H-2 percentages suggest that the rate coefficient for the gas-pha se reaction CFx + H --> CFx-1 + HF is much smaller than the values rep orted in literature.